Straightarrow

This is related to the post where I described a spine tester that I built. To test the value of spine-tuned arrows, I fletched a dozen Gold Tip Hunters 7595 and shot them at various distances with 125 gr. 2-blade Magnus Stingers. I decided on these lower priced carbons, which are reputed to have poor spine consistency.

I asked for input on what an acceptable spine variance would be, and didn't get an answer yet, so I decided to test some of the arrows that had more variance than the others. I choose five arrows where the weakest and strongest sides were between .008 and .015 difference. I have no idea if this falls in a good or bad range, but I figured these were no better than average for a dozen GT hunters. Out of the dozen, there were 6 other arrows that measured more consistant than these and one that measured much worse.

After testing with the spine tester, I marked the weak side of each arrow and placed the cock fletch on that mark. I used 4" feathers attached with a helical clamp. Draw weight was 65 lbs out of a hybrid cam bow. Draw length was 28.5" and arrow length was 28.75". The bow was well-tuned and shooting field tips very well if I did my part. A whisker biscut was used as the rest. A mechanical release was used. I shot the 5 arrows with the Stingers attached, at broadhead targets set at 20, 40 and 60 yards. The arrows were shot one at a time and then marked. I wanted to determine group size and location without actually shooting a group. A total of 3 groups were shot at each distance and averaged to determine group size and location.

To start, no tuning adjustments were made and the sight was not adjusted. At 20 and 40 yards I could tell no difference in group location between these arrow and my field tipped arrows. The sight needed absolutely no adjustment and no tuning adjustments were made either. The group size at these distances was actually a bit smaller than my normal field tip group. It is likely I was just having a good day shooting, but all five arrows flew nicely into the group. Normally, I'd shoot a dozen, culling them down to the best 4 or 5 shooters in the bunch. I found it refreshing that none of these appears to need to be culled.

At 60 yards the group location was still right one, but it did widen to a bit more than normal. There was about a 15 mile per hour wind that may have been influencing them at this distance.

Overall, I was very impressed with how these cheap carbons flew when spine-tuned. This test was certainly not conclusive of anything, but it did give me reason for optimism. I'll be shooting these a lot over the next couple weeks (before the season opens), to try and determine if these were just better than normal arrows for a Gold Tip Hunter, or if the spine tester will prove to be very useful.

Len in Maryland

I see that you decided to use an over-spined arrow. Was there a reason for this?

Did you spin-test your arrows? Did you cut some lenght off the nock end before you cut-to-length? Did you check the arrows for consistent weight?

Did you use a Hooter Shooter? Are you going to test again on a non-windy day?

Do you plan to test other arrows?

Just a few questions that crossed my mind.

Straightarrow

In my opinion, a 125 gr tip on a 29" shaft at 65 lbs is borderline for a 5575. I know their chart says otherwise, but I've bareshaft tested them many times and this is the area where 5575's start flying as a weak shaft in my testing. When shooting a broadhead, I prefer to be on the stiff side, which seems to be more forgiving. I've noticed when checking spine, that the weakest arrow and the stiffest arrow were quite far apart. The weakest measured approx. .340 and the strongest was .315. With a difference this great, I suspect a wider group in a borderline spine situation.

Yes, but I'm not sure how to do this properly. I have an Arizona Archer Arrow Straightener, that I can test the straightness with, but it's over a relatively short span. These actually tested as much straighter than specs, but like I said, I don't know how the specs are obtained.

Yes, and this is something I've just recently started doing (because of advise on this forum). This may have also positively affected my results and may have been one of the reasons I had to cull so many arrows in the past.

Yes, and a couple were not within specs, but were close. I forgot to mark which ones, and they are still in the dozen.


Nope, wish I had one, but I had to rely on the results obtained from my inconsistent shooting. This is why I will try to shoot them a lot over the next couple weeks, to see if I notice any significant changes.

Well, I've have to see if the wind stops blowing. I can shoot up to 30 yards indoor at the local range, but the longer shots will have to wait for more co-operative weather.

I doubt I'll buy any others for a few months. I frequently work on friend's equipment, so I'm going to spread the word that I'm willing to spine test, and build their arrows, if they'll allow some broadhead testing with them. I'll have to see what happens on this.

I appreciate the interest and invite any input you have.

Stryker777

Thanks for the info Straight! It is very nice to get some factual data that is not from the companies. Even with variables that may curb results, your test show valuable information for use in the real enviroment. We can do all we want in a stable enviroment, but without testing in the real world also, we will see a new world in the field. I agree base data from controlled tests would be nice for comparison, but the data you presented is very helpful. Base data we can normally get from a company with a small curve.
Stryker777

Arthur P

I do the same thing, only I align my cock feather over the stiffest axis of the shaft. I've seen some improvement with my carbon arrow accuracy since I began doing that but, like you, I don't have a Hooter Shooter for definitive analysis.

Straightarrow

This was a dilemma that I had. I first went through the group and tested 4 sides on each arrow and noted what they were. When done I found a few that had 3 similar sides and one weaker one. The were a couple that had 3 similar sides and one stronger one. I could have gone either way. I also wondered if it would be best the find a side that was the same on all arrows. For instance, if most arrows had one side that tested .330, maybe it would be best to put the cock feather on a spine that was the same on each arrow, regardless of whether it was weak or strong compared to the other sides. Down the road, I hope to try that on a dozen to see what the results are.

Straightarrow

Arthur, I forgot to ask, what kind of variance have you found on the carbons you've tested?

Rangeball

Not to speak for Art, but he has to duct tape two arrows together to get his draw length, so your mileage may vary...

Arthur P

Which is a problem I wouldn't have if them yayhoos would just make shafts long enough in the first place.[>:]

Straightarrow, the worst I've gotten has been .035 variance. But I've only gotten that on one arrow out of the dozens I've checked. Tossing it out as an abberration, the average has been around .012 or so. Still about a 5 pound spine difference from one axis of the shaft to the next. Really critical if you're on the very top edge of an arrow's spine rating!

That's a big reason why so many people recommend jumping up to the next stiffest size if you're right on the edge - whether they know that's the reason or not is questionable though. I have to admit I didn't know it, until I got my spine tester and gave it some serious thought.

Straightarrow

Your results are amazingly similar to mine. I came to the same conclusion with the stiffer arrows. When you're spinning the arrows on the tester and seeing one at .340 and another at .325 or even .315, it becomes very obvious that in a borderline spine situation, the weaker ones are not going to fly the same way the strong ones will. It makes good sense that they should all be strong.

I've been shooting these for a few days now, and even with broadheads, I am still getting groups that are smaller than what I would normally get with field tips on the same arrows. I did get to shoot on a day with little or no wind and my 60 yards groups were very good (for me).